This invention relates generally to methods and apparatus for producing flexible packaging. More particularly, this invention relates to methods and apparatus for the continuous production of flexible packaging wherein each individual package contains a vacuum sealed controlled quantity of a non-solid substance. Representative of such substances are ointments and salves, for example.
It is the nature of flexible packaging of the type contemplated herein that two webs are joined together and prior to the joining, a vacuum is applied so as to provide the desired sealed evacuated flexible package as the resulting or ultimate product. In providing such packaging in the past, it has been appropriate to join together the webs in a horizontal relationship along a production line and to continuously form across the breadth of the webs being joined together a plurality of packages simultaneously. In doing so, a manifold applies to the webs a vacuum immediately prior to the two webs being sealed and the individual packages cut from the joined webs. Such procedures provide a desirable package with an appropriate quantity of the material contained therein under the proper sealed evacuated conditions. However, such procedures are cumbersome and time consuming in this day of producing multiple quantities of flexible packaging for various applications.
It is important that a precise controlled quantity of material be contained in each individual package if, for example, the ointment or salve is a medication requiring a precise controlled quantity for later medical application to a patient. Such applications include, for example, transdermal medication in which a flexible package includes a special membrane with an adhesive surface which may be applied to the skin of a patient for a controlled administration of a medication over a period of time. Such flexible packages include a peel-off film over the adhesively surfaced membrane which the user peels off immediately prior to applying the package to his skin.
As will be appreicated, such packages must have a precise controlled quantity of an ointment containing the medication so as to provide the proper amount of medication over a period of time. Supplying and joining the webs appropriate for producing such packaging together in a horizontal flat orientation and going through this sequential application of vacuum, insertion of the material involved, and the sealing of the various packages together is a somewhat cumbersome process requiring a rather slow output or production of such flexible packages.
By contrast, with the invention herein, methods and apparatus are provided for the continuous and rapid production of a plurality of such flexible packages containing a non-solid material by joining the two webs together in the nip of sealing rolls. That is, a plurality of such packages are formed simultaneously across the width of the webs being joined together in the roller nip which cooperate to provide automatically and simultaneously the formation, evacuation and sealing of each individual flexible package in the webs. By utilizing a joining together in the nip of cooperating rolls, a much larger quantity of flexible packages may be produced on a continuous basis in a much more simplified manner. The invention contemplates the use of cooperating sealing rollers in which one roll includes pockets for forming the individual flexible packages cooperating with a second roll which provides a proper pressure at the nip of the rolls in order to form the individual packages across the width of the webs being joined.
It has been found that by the use of the specific kind of cooperating rollers, in accordance with this invention, that no special vacuum application need be made and that the flexible packages are formed automatically and continuously in the cooperating roller nip. In doing so, individual quantities of the medication, salve or ointment to be incorporated into the packages is applied to one web immediately prior to the cooperating roller nip. Thereafter, the individual quantities on the web pass into the roller nip and are incorporated into the individual packages. The individual quantities of medication move into the related pockets on the opposed roller at the cooperating nip so as to provide automatically between the webs being joined an individual evacuated pocket containing the ointment or material to be contained in the packages. As the individual pockets pass into the nip, the two webs are joined together and sealed automatically around the rim of the pockets, as will be discussed in more detail below.
It will be understood by practitioners-in-the-art, that the webs contain thermoplastic resin materials which may be joined and sealed under the application of heat and pressure. The crimp rolls which cooperate to provide the sealed packaging on a continuous basis are heated in order to provide the appropriate sealing of the two webs together during the simultaneous forming, evacuation and sealing of the flexible packages. Once the two webs are joined together, the webs are slit longitudinally into a plurality of strips each containing therealong in spaced fashion a plurality of formed and sealed flexible packages. Subsequent to the slitting of the individual elongated strips from the originally joined webs, the web strips pass through a knife station which cuts the individual packages from their elongated web strip for collection and inspection.
Before describing this invention in more detail, it may be well to note that the flexible packaging procedures involved herein apply to a variety of different materials which may be packaged, as long as they contain a liquid component. That is, ointments, salves and even oils may be contained within the flexible packaging herein, as long as the material involved will, when dropped on the web and prior to being sealed in the roller nips, hold a momentary self-contained body until such time as the material is properly joined in the evacuated flexible packaging formed by the methods and apparatus herein. It will be understood, furthermore, that a variety of different film materials comprised of thermoplastics may be utilized in the processing of the invention herein for forming the webs which are joined together to produce the flexible packaging. For example, polyvinyl chloride, polyvinylidene chloride, polyesters, polyethylene and polypropylene are all materials which may be utilized.
With the foregoing and additional objects in view, this invention will now be described in more detail, and other objects and advantages thereof will be apparent from the following description, the accompanying drawings, and the appended claims.
As purely illustrative of apparatus which may be used for carrying out the process of this invention, one may note the attached drawings in which a schematic illustration of apparatus for carrying out the invention is shown together with a representative example of one of the crimp rolls which cooperate to produce the flexible packaging of the invention. Also, a representative package which may be formed in accordance with this invention is shown and described.